Known rotary snow tillers for grooming ski slopes normally advance in a traveling direction along the ski slope, and comprise a frame; and a toothed shaft rotated with respect to the frame about an axis crosswise to the traveling direction.
Such known rotary snow tillers have proved particularly effective in grooming ski slopes. The snow covering, however, varies considerably with weather conditions, snowfall and, particularly, daily variations in temperature. In the case of a steep temperature swing on either side of zero degrees, the snow covering forms an icy surface crust which, when particularly thick, impairs performance, in terms of quality grooming, of these known rotary snow tillers.